O-phosphoserine

Endpoint summary

Key value for chemical safety assessment

Genetic toxicity in vitro

Description of key information

In an bacterial reverse mutation assay (Ames test), 5 different bacteria strains (S. typhimurium TA 1535, TA 1537, TA 98, TA 100, and E.coli WP2 uvrA) were incubated with doses up to 5000 µg/plate of the test item, with or without metabolic activation (S9 mix) according to OECD Guideline 471 (reference 7.6.1 -1). No significant increase in the numbers of revertant colonies was recorded. The test substance was found to be non-mutagenic under test conditions.

Link to relevant study records

Reference

Endpoint:

in vitro gene mutation study in bacteria

Type of information:

experimental study

Adequacy of study:

key study

Study period:

2017-03-07 to 2017-05-22

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

guideline study

Qualifier:

according to guideline

Guideline:

OECD Guideline 471 (Bacterial Reverse Mutation Assay)

Version / remarks:

1997

Deviations:

no

GLP compliance:

yes

Type of assay:

bacterial reverse mutation assay

Specific details on test material used for the study:

OTHER SPECIFICS: white powder

Target gene:

his/trp

Species / strain / cell type:

S. typhimurium TA 1535, TA 1537, TA 98, TA 100 and E. coli WP2

Remarks:

uvrA

Metabolic activation:

with and without

Metabolic activation system:

S9 mix, male Wistar rat pretreated with beta-Naphthoflavone/Phenobarbital

Test concentrations with justification for top dose:

The test material concentrations used were selected according to the EEC, OECD and Japanese guidelines for this test system.
A maximum concentration of 5000 µg/plate was selected, in order that initial treatments were performed up to the maximum recommended concentration according to current regulatory guidelines (OECD TG 471, 1997).
1st series: 5.0, 15.8, 50.0, 158, 500, 1580, 5000 µg/plate, 10% S9 mix
2nd series: 50.0, 158, 500, 1580, 5000 µg/plate, 20% S9 mix

Vehicle / solvent:

- Vehicle(s)/solvent(s) used: water
- Justification for choice of vehicle: Comparing the standard solvents for this assay indicated that the test substance showed best solubility performance in ultra-pure water. Based on these preliminary data, ultra-pure water was selected as vehicle for the current experiment.

Untreated negative controls:

no

Negative solvent / vehicle controls:

yes

True negative controls:

no

Positive controls:

yes

Positive control substance:

other: Dauromycin

Remarks:

1.0 µg/plate, TA98, wihthout S9 mix

Untreated negative controls:

no

Negative solvent / vehicle controls:

yes

True negative controls:

no

Positive controls:

yes

Positive control substance:

sodium azide

Remarks:

2.0 µg/plate, TA100, TA1535, without S9 mix

Untreated negative controls:

no

Negative solvent / vehicle controls:

yes

True negative controls:

no

Positive controls:

yes

Positive control substance:

9-aminoacridine

Remarks:

50.0 µg/plate, TA1537, without S9 mix

Untreated negative controls:

no

Negative solvent / vehicle controls:

yes

True negative controls:

no

Positive controls:

yes

Positive control substance:

4-nitroquinoline-N-oxide

Remarks:

2.0 µg/plate, E. coli, without S9 mix

Untreated negative controls:

no

Negative solvent / vehicle controls:

yes

True negative controls:

no

Positive controls:

yes

Positive control substance:

other: 2-Aminoanthracene

Remarks:

2.0, 5.0, 10.0 µg/plate, all strains, with S9 mix

Details on test system and experimental conditions:

METHOD OF APPLICATION: in agar (plate incorporation)

DURATION
- Exposure duration: 2 - 3 days at 36 - 38 °C

SELECTION AGENT (mutation assays):
Commercially available Minimal-Glucose-Agar plates (Art. 146690, Charge 143118, Merck Life Science, 69214 Eppelheim, Germany) were used for all strains.

NUMBER OF REPLICATIONS: 3

Evaluation criteria:

The assessment of test material-induced effects is dependent on the number of spontaneous re-vertants of each bacteria strain (solvent controls) and the increase in the number of revertants at the test material concentration which shows the highest number of colonies. The following criteria, based upon the historical controls of the laboratory and statistical considerations, are established (see "Any other information on materials and methods").

Key result

Species / strain:

S. typhimurium TA 98

Metabolic activation:

with and without

Genotoxicity:

negative

Cytotoxicity / choice of top concentrations:

no cytotoxicity nor precipitates, but tested up to recommended limit concentrations

Vehicle controls validity:

valid

Untreated negative controls validity:

not examined

Positive controls validity:

valid

Key result

Species / strain:

S. typhimurium TA 100

Metabolic activation:

with and without

Genotoxicity:

negative

Cytotoxicity / choice of top concentrations:

no cytotoxicity nor precipitates, but tested up to recommended limit concentrations

Vehicle controls validity:

valid

Untreated negative controls validity:

not examined

Positive controls validity:

valid

Key result

Species / strain:

S. typhimurium TA 1535

Metabolic activation:

with and without

Genotoxicity:

negative

Cytotoxicity / choice of top concentrations:

no cytotoxicity nor precipitates, but tested up to recommended limit concentrations

Vehicle controls validity:

valid

Untreated negative controls validity:

not examined

Positive controls validity:

valid

Key result

Species / strain:

S. typhimurium TA 1537

Metabolic activation:

with and without

Genotoxicity:

negative

Cytotoxicity / choice of top concentrations:

no cytotoxicity nor precipitates, but tested up to recommended limit concentrations

Vehicle controls validity:

valid

Untreated negative controls validity:

not examined

Positive controls validity:

valid

Key result

Species / strain:

E. coli WP2 uvr A

Metabolic activation:

with and without

Genotoxicity:

negative

Cytotoxicity / choice of top concentrations:

no cytotoxicity nor precipitates, but tested up to recommended limit concentrations

Vehicle controls validity:

valid

Untreated negative controls validity:

not examined

Positive controls validity:

valid

Table 2: Summary 1st series

Metabolic activation	Test Material	Concentration [µg/plate]	Revertants per plate (Mean± SD)
			TA98	TA100	TA1535	TA1537	E. coli
Without S9 mix	H2O		37± 10	124± 10	24± 4	8± 3	33± 7
	Test Substance	5.0	36± 2	106± 10	23± 2	7± 1	37± 1
		15.8	35± 3	115± 11	22± 7	6± 3	38± 6
		50.0	29± 12	21± 4	22± 6	8± 2	44± 3
		158	38± 3	117± 13	19± 10	7± 2	37± 13
		500	29± 7	102± 11	26± 3	11± 7	41± 6
		1580	31± 4	105± 6	21± 8	12± 6	34± 9
		5000	26± 12	121± 6	22± 4	7± 1
	DAUN	1.0	186± 8
	NaN3	2.0		1470± 72	819± 22
	9-AA	50.0				561± 221
	NQO	2.0					1566± 53
With S9 mix	H2O		44± 7	132± 8	22± 4	7± 1	35± 5
	Test Substance	5.0	40± 7	120± 19	25± 5	5± 4	37± 4
		15.8	36± 1	135± 12	18± 2	7± 1	42± 3
		50.0	39± 6	149± 14	22± 3	10± 4	49± 10
		158	37± 2	127± 9	17± 3	10±4	41± 2
		500	46± 5	118± 9	25± 5	11± 4	38± 5
		1580	36± 4	132± 21	21± 4	12± 6	40± 12
		5000	46± 11	130± 16	21± 9	10± 2	42± 2
	2-AA	2.0	741± 59	1014± 140
	2-AA	5.0			196± 31	442± 25
	2-AA	10.0					373± 64

NaN3, Sodium azide

2 -AA, 2-Aminoanthracane

9 -AA, 9-Aminoacridine

DAUN, Daunomycin

NQO, 4-Nitroquinoline-N-oxide

Table 3: Summary 2nd series

Metabolic activation	Test Material	Concentration [µg/plate]	Revertants per plate (Mean± SD)
			TA98	TA100	TA1535	TA1537	E. coli
Without S9 mix	H2O		40± 7	145± 15	35± 5	7± 3	34± 9
	Test Substance	50.0	47± 9	158± 12	37± 7	5± 1	28± 5
		158	39± 6	164± 34	37± 11	7± 2	36± 8
		500	30± 2	150± 16	34± 1	7± 3	34± 3
		1580	40± 8	134± 14	30± 2	6± 1	35± 9
		5000	45± 7	163± 27	31± 5	8± 2	42± 3
	DAUN	1.0	379± 89
	NaN3	2.0		1731± 42	1048± 45
	9-AA	50.0				565± 109
	NQO	2.0					1960± 25
With S9 mix	H2O		58± 11	131± 14	24± 9	9± 3	40± 10
	Test Substance	50.0	51± 14	155± 18	28± 5	9± 1	43± 6
		158	47± 12	141± 4	20± 6	8± 2	33± 4
		500	57± 3	141± 4	29± 6	5± 2	40± 4
		1580	55± 14	131± 13	27± 5	10± 4	36± 6
		5000	42± 4	133± 5	20± 3	9± 2	38± 8
	2-AA	2.0	362± 13	598± 16
	2-AA	5.0			188± 24	126± 28
	2-AA	10.0					192± 4

NaN3, Sodium azide

2 -AA, 2-Aminoanthracane

9 -AA, 9-Aminoacridine

DAUN, Daunomycin

NQO, 4-Nitroquinoline-N-oxide

Conclusions:

In an in vitro bacterial reverse mutation assay (Ames test) according to OECD Guideline 471 with and with out metabolic activation (S9 mix), the test substance showed no mutagenic potential.

Executive summary:

The investigations for the mutagenic potential of the test item were performed using Salmonella typhimurium test strains TA 98, TA 100, TA 1535 and TA 1537, and Escherichia coli WP2 uvrA according to OECD Guideline 471 (reference 7.6.1 -1). The plate incorporation test with and without addition of liver S9 mix from rats pretreated with beta-Naphthoflavone/Phenobarbital was used. In this study, two experimental series were performed. The S9 mix used contained 10% S9 in the 1st and 20% S9 in the 2nd series, respectively. Treatments of all test strains were performed using the test item prepared in ultra-pure water in the absence and in the presence of S9 mix, using final concentrations of 5.0, 15.8, 50.0, 158, 500, 1580, and 5000 µg/plate, plus vehicle and positive controls. Solvent and positive control treatments were included and valid for all strains. The mean numbers of revertant colonies all fell within acceptable ranges for solvent control treatments, and were clearly elevated by positive control treatments, thus, showing the expected reversion properties of all strains and good metabolic activity of the S9 mix used. Following treatment of all bacteria test strains with the test substance in the absence and presence of S9 mix, no relevant increases in revertant numbers were observed.Furthermore, it was assumed, that the anhydrate form has the same mutagenic potential and thus the result of the test item is also applicable.

Endpoint conclusion

Endpoint conclusion:

no adverse effect observed (negative)

Additional information

The investigations for the mutagenic potential of the test item were performed using Salmonella typhimurium test strains TA 98, TA 100, TA 1535 and TA 1537, and Escherichia coli WP2 uvrA according to OECD Guideline 471 (reference 7.6.1 -1). The plate incorporation test with and without addition of liver S9 mix from rats pretreated with beta-Naphthoflavone/Phenobarbital was used. In this study, two experimental series were performed. The S9 mix used contained 10% S9 in the 1st and 20% S9 in the 2nd series, respectively. Treatments of all test strains were performed using the test item prepared in ultra-pure water in the absence and in the presence of S9 mix, using final concentrations of 5.0, 15.8, 50.0, 158, 500, 1580, and 5000 µg/plate, plus vehicle and positive controls. Solvent and positive control treatments were included and valid for all strains. The mean numbers of revertant colonies all fell within acceptable ranges for solvent control treatments, and were clearly elevated by positive control treatments, thus, showing the expected reversion properties of all strains and good metabolic activity of the S9 mix used. Following treatment of all bacteria test strains with the test substance in the absence and presence of S9 mix, no relevant increases in revertant numbers were observed. Furthermore, it was assumed, that the anhydrate form has the same mutagenic potential and thus the result of the test item is also applicable.

Justification for classification or non-classification

Classification, Labeling, and Packaging Regulation (EC) No 1272/2008

The available experimental test data are reliable and suitable for classification purposes under Regulation (EC) No 1272/2008. In vitro results with the test substance were negative. As a result the test substance is not considered to be classified for genetic toxicity under Regulation (EC) No 1272/2008, as amended for the tenth time in Regulation (EU) No 2017/776.